Event 8365 from MSExchangeAL - Could not read the Security Descriptor

I checked our Exchange server, and found no child objects under CN=Connections.  Even though the presence of an invalid mailgateway may trigger Event 8365, I think that is not the only, or even the most common, trigger.  I still think the strongest correlation with Event 8365 is Event 9661 - "The Unsolicited Commercial Email default filter level has been updated. The new value is 4".